Werewolf by Night's introduction to the MCU is also huge because in the comics, he is part of a team called the Midnight Sons, which has consisted of characters like Blade, Morbius, Ghost Rider, Scarlet Witch, Moon Knight, Doctor Strange, and more. Also, in recent comics featuring the group, they have met up with Agatha Harkness, Clea Strange, and more.
Marvel / Disney+
All of these characters have been introduced or WILL be introduced in the MCU, so big eyes emoji from me here 👀.